<template>
  <div class="xtx-carousel" @mouseenter="stop()" @mouseleave="start()">
    <!--轮播图图片容器-->
    <ul class="carousel-body">
    <!--fade  显示的图片加上-->
      <li class="carousel-item" v-for="(item,i) in sliders" :key="i" :class="{fade:index===i}">
        <!-- 图片 -->
        <RouterLink v-if="item.imgUrl" :to="item.hrefUrl"  >
          <img
            :src="item.imgUrl"
            alt=""
          />
        </RouterLink>
        
      </li>
    </ul>
    <!--上一张-->
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev">
      <i class="iconfont icon-angle-left"></i>
    </a>
    <!--下一张-->
    <a @click="toggle(+1)" href="javascript:;" class="carousel-btn next">
      <i class="iconfont icon-angle-right"></i>
    </a>
    <!--指示器-->
    <div class="carousel-indicator">
    <!--active 激活点-->
      <span @click="index=i" v-for="(item,i) in sliders" :key="i" :class="{active:index===i}"></span>
    </div>
  </div>
</template>

<script>
import {onUnmounted, ref,watch} from 'vue'
export default {
  name: 'DjCarousel',
  props:{
    // 1.轮播图数据
    sliders:{
      
      type:Array,
      default:()=>[]
    },
    // 是否自动轮播
    autoPlay:{
      type:Boolean,
      default:false
    },
    // 间隔时长
    duration:{
      type:Number,
      default:3000
    }
  },
  setup(props){
    // console.log(props.sliders);
    // 控制显示图片的索引
    const index =ref(0)
    // 自动轮播图的逻辑
    let timer=null
    const autoPlayFn=()=>{
      clearInterval(timer)
      //自动播放，每隔多久切换索引
      timer=setInterval(()=>{
        index.value++
        if(index.value>=props.sliders.length){
          index.value=0
        }
      },props.duration)
    }
    //需要监听sliders数据变化，判断如果有数据且autoplay是true
      watch(()=>props.sliders,(newVal)=>{
        if(newVal.length && props.autoPlay){
          autoPlayFn()
        }
      },{immediate:true})
    // 2.鼠标进入暂停，离开开启自动播放(有开启条件)
    const stop=()=>{
      if(timer) clearInterval(timer)
    }
    const start=()=>{
      if(props.sliders.length && props.autoPlay) autoPlayFn()
    }
    // 3.点击点点可以切换，上一张下一张
    const toggle=(step)=>{
      // 将要改变的索引
      const newIndex=index.value+step
      // 超出的情况，太大了
      if(newIndex>(props.sliders.length-1)){
        index.value=0
        return
      }
      // 超出的情况，太小了
      if(newIndex<0){
        index.value=props.sliders.length-1
        return
      }
      // 正常
      index.value=newIndex
    }
    // 4.组件卸载，消除定时器
    onUnmounted(()=>{
      clearInterval(timer)
    })
    return {index,stop,start,toggle}
  }
}
</script>

<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>